Field
Embodiments described herein generally relate to thermal processing of substrates. More specifically, embodiments provided herein relate to an apparatus for pyrometer background elimination.
Description of the Related Art
A number of applications involve thermal processing of semiconductor and other materials, which require precise measurement and control of the temperature of the materials being thermally processed. For instance, processing of a semiconductor substrate requires precise measurement and control of the temperature over a wide range of temperatures. One example of such processing is rapid thermal processing (RTP), which is used for a number of fabrication processes, including rapid thermal annealing (RTA), rapid thermal cleaning (RTC), rapid thermal chemical vapor deposition (RTCVD), rapid thermal oxidation (RTO), and rapid thermal nitridation (RTN).
Temperature uniformity across the surface of the substrate is important for thermal processing. For example, it is desirable to have temperature variations of less than about 3° across the surface of the substrate to improve thermal processing results. Conventional substrate supports that support a substrate in RTP processes generally contact the substrate around the circumference of the substrate. The contact between the substrate support and the substrate can create temperature non-uniformities near the edge of the substrate. To overcome the temperature non-uniformities associated with the physical contact between the substrate support and the substrate, various other methods which minimize contact between the support and the substrate may be utilized. However, these methods allow for excess background radiation to propagate beyond the substrate. The excess radiation may interfere with temperature metrology devices and skew temperature measurements of the substrate.
Thus, what is needed in the art are apparatuses for supporting a substrate with minimal physical contact and for reducing or eliminating background radiation to improve temperature measurement of an RTP system.